<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="./js/vue.js"></script>
  </head>
  <body>
    <div id="app">
      <App></App>
    </div>
  </body>
</html>
<script>
  Vue.config.productionTip = false;

  const Header = Vue.extend({
    name: 'Header',
    template: `
      <h2>我是头部Header</h2>
    `,
  });

  const App = Vue.extend({
    name: 'App',
    components: {
      Header,
    },
    template: `
      <div>
        <h1>App {{message}}</h1>
        <Header></Header>
      </div>
    `,
    data() {
      return {
        message: 'hello',
      };
    },
  });

  console.log(App, 'App'); // VueComponent构造函数

  const vm = new Vue({
    el: '#app',
    components: {
      App,
    },
    data() {
      return {};
    },
  });
</script>
